2000
#1,628
National surname rank
Recorded bearers 20,135
First available Census row
Per 100,000 7.46
Uncommon Last name
Mcwilliams
Son of William, an English and Scottish patronymic surname.
According to the 2020 US Census Bureau surname tables, roughly 22,346 Americans carry the last name Mcwilliams. That puts it at #1,803 in the national surname ranking, appearing at a frequency of 6.52 per 100,000 people (about 1 in 15,339 residents).
This page is the full Name Census profile for the Mcwilliams surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
For British records, Name Census UK has a British surname profile for Mcwilliams with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
22K
1 in 15,339
Census rank
#1,803
2020 decennial data
Per 100,000
6.5
Frequency rate
Recorded bearers
19K
uncommon in the US
Popularity narrative
The Census Bureau recorded 19,487 bearers of the surname Mcwilliams in its 2020 decennial surname file. At a rate of 6.52 per 100,000 residents, it holds the 1803rd position in the national surname ranking.
Among Census respondents with the surname Mcwilliams, the largest self-reported group is White at 74.6%. The next largest groups are Black (16.7%) and Two or More Races (3.9%).
Origin
Meaning and origin of Mcwilliams
The surname McWilliams has its origins in Scotland, emerging during the Middle Ages. It is a patronymic name, derived from the personal name "William," which itself is of Germanic origin, meaning "resolute protector." The prefix "Mc" or "Mac" is a Gaelic form meaning "son of," indicating that the name originally referred to the son of a man named William.
McWilliams is a common surname in the Scottish Highlands, particularly in areas such as Argyll, Ayrshire, and the Hebrides islands. It is thought to have originated in these regions, where the name can be traced back to the 12th and 13th centuries.
Historical records suggest that the McWilliams clan was associated with the powerful Clan Donald, one of the largest and most influential Scottish clans. The earliest known record of the name appears in the Ragman Rolls of 1296, which documented the Scottish barons who swore allegiance to King Edward I of England.
In the 16th century, a notable figure bearing the McWilliams name was Sir John McWilliams, a Scottish knight who fought alongside King James IV at the Battle of Flodden in 1513. Another prominent McWilliams was William McWilliams, born in 1642, who served as a Presbyterian minister and played a significant role in the Scottish Reformation.
As the centuries passed, the McWilliams surname spread throughout Scotland and beyond. In the 17th century, during the plantation of Ulster, many Scottish settlers, including those with the McWilliams name, migrated to Ireland, establishing roots in counties like Antrim and Down.
Notable McWilliams individuals include:
1. Sir William McWilliams (1795-1869), a British naval officer and explorer who surveyed parts of the Australian coast.
2. John McWilliams (1839-1914), an Irish-American architect known for designing several prominent buildings in New York City.
3. Carey McWilliams (1905-1980), an American author and editor who wrote extensively on social and political issues in California.
4. Jeremiah McWilliams (1712-1786), an Irish-born American soldier who served in the Continental Army during the American Revolutionary War.
5. Malcolm McWilliams (1891-1981), a Canadian politician who served as a member of the House of Commons of Canada.
The McWilliams surname has endured through the centuries, and its Scottish roots and rich history continue to be celebrated by those who bear this name today.
Demographics
Ancestry and ethnicity for Mcwilliams
Among Census respondents with the surname Mcwilliams, the largest self-reported group is White at 74.6%. The next largest groups are Black (16.7%) and Two or More Races (3.9%).
The bar chart below shows how Mcwilliams bearers described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Mcwilliams surname at the time of the 2020 Census, not any inherent property of the name itself.
- White74.6% · 14,545
- Black or African American16.7% · 3,262
- Two or more races3.9% · 766
- Hispanic or Latino3.4% · 670
- Asian and Pacific Islander0.7% · 136
- American Indian and Alaska Native0.6% · 108
Timeline
Historical Census data for Mcwilliams
Mcwilliams appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#1,746
National surname rank
Recorded bearers 20,523
+388 bearers (+1.9%)
Per 100,000 6.96
Rank movement Down 118 places
2020
#1,803
National surname rank
Recorded bearers 19,487
-1,036 bearers (-5.0%)
Per 100,000 6.52
Rank movement Down 57 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #1,628 | 20,135 | 7.46 | First available Census row | First available Census row |
| 2010 | #1,746 | 20,523 | 6.96 | +388 bearers (+1.9%) | Down 118 places |
| 2020 | #1,803 | 19,487 | 6.52 | -1,036 bearers (-5.0%) | Down 57 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Mcwilliams surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #1,746 | #1,803 | -3.3% |
| Count | 20,523 | 19,487 | -5.0% |
| Per 100K | 6.96 | 6.52 | -6.3% |
Between the 2010 and 2020 Census, the number of Mcwilliams bearers went from 20,523 to 19,487 (-5.0% change). The surname moved down 57 positions in the national ranking, going from #1,746 to #1,803.
FAQ
Mcwilliams surname: questions and answers
How many people in the U.S. have the surname Mcwilliams?
Name Census estimates that about 22,346 living Americans carry the surname Mcwilliams. Using the current population baseline, that works out to roughly 1 in 15,339 residents.
How common is Mcwilliams?
Mcwilliams ranks #1,803 in the 2020 Census surname tables and is classified on this site as "Uncommon." The Census recorded the name at a frequency of 6.52 per 100,000 residents, which is about 7 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 19,487 people with the surname Mcwilliams. That is different from the site's living-bearer estimate (22,346), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 6.52 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 6.52 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 7 of them to have the surname Mcwilliams.
Has Mcwilliams become more or less common over time?
Between 2010 and 2020, the surname Mcwilliams went from 20,523 recorded bearers to 19,487. That is a decrease of 1,036 (-5.0%). In the national ranking it fell from #1,746 to #1,803.
What does the Census say about the background of Mcwilliams?
Among Census respondents with the surname Mcwilliams, the largest self-reported group is White at 74.6%. The next largest groups are Black (16.7%) and Two or More Races (3.9%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
White is the largest self-reported group for the surname Mcwilliams in the 2020 Census, accounting for 74.6% (14,545 people in the source table).
What is the full ancestry breakdown?
Mcwilliams appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (74.6%), Black (16.7%), Two or More Races (3.9%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Mcwilliams (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Mcwilliams mean?
Son of William, an English and Scottish patronymic surname. The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Mcwilliams (6.52 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How many people have the surname Mcwilliams?
For a quick modern estimate, our sister site HowManyOfMe.org answers that in one glance, with the living-bearer count front and centre.